Indexible turning tool for chipforming machining

ABSTRACT

An indexible turning tool for chip forming machining, includes a holder equipped with insert pockets receiving replaceable inserts, as well as a securing portion intended to be received in a tool machine. At least one of the replaceable inserts has a main plane that extends laterally in relation to the tool&#39;s axial direction.

This application claims priority under 35 U.S.C. §§119 and/or 365 topatent application Ser. No. 0203199-5 filed in Sweden on Oct. 31, 2002,the entire content of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

The present invention relates to a turning tool for chip formingmachining, wherein the tool includes a holder, which is equipped withinsert pockets for occupying interchangeable inserts, as well as asecuring portion, which is intended to be received in a tool machine.The turning tool according to the present invention is preferablyintended for metal machining.

In a brochure from Mapal published in September 2002 there is previouslyknown a milling tool for chip forming machining, wherein said millingtool has inserts oriented laterally from a longitudinal axial directionfor the tool, i.e., they are situated on the front surface of saidmilling tool. It shall be emphasized in this connection that it is arotary tool, and therefor the forces which affect the inserts are notcomparable to the forces which affect an insert on a turning tool.

A primary purpose of the present invention is to provide a turning toolof the above-captioned type, which promotes the tool's availability fordifferent machining operations.

Another purpose of the present invention is to reduce the setting timebetween different types of working operations, for example turning andthreading

SUMMARY OF INVENTION

At least the primary purpose of the present invention is achieved by anindexible turning tool which comprises a tool body that includes asecuring portion and a holder. The holder is provided with pockets whichreceive respective replaceable cutting inserts. The pockets are arrangedwherein indexing of the tool body about a longitudinal center axis ofthe holder brings one of the inserts into an operative cutting position.One of the inserts has a main plane oriented laterally relative to theholder's center axis.

DESCRIPTION OF THE DRAWINGS

A number of embodiments of the tool according to the present inventionare described below, wherein reference is made to the drawings.

FIG. 1 shows, in a perspective view, an embodiment of an indexibleturning tool according to the present invention.

FIG. 2 shows a detail of the cutting head of the tool according to FIG.1; wherein the cutting head is provided with three exchangeable(replaceably) inserts.

FIG. 3 shows a detail.

FIG. 4 shows a detail of an alternatively cutting head.

FIG. 5 shows, in a perspective view, an alternative embodiment of a toolaccording to the present invention, wherein the tool is in engagementwith a workpiece and the forces acting on the tool.

FIG. 6 shows in detail the cutting head of the tool according to FIG. 5.

FIG. 7 shows how the tool according to FIG. 5 is used in threading.

FIG. 8 shows in a perspective view an alternative tool according to thepresent invention, where two replaceable inserts are oriented accordingto principles of the present invention.

FIG. 9 shows, in a perspective view, the tool according to FIG. 8 duringmachining of a rotary work piece.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

The present invention relates to a turning tool, wherein a “turningtool” of the present invention shall understood to be a non-rotary toolwhich for example can perform cutoff operations, grooving, turn milling,etc. The turning tool is indexible about a longitudinal center axis toenable one of a plurality of exchangeable cutting inserts to be placedin an operative cutting position. Additionally, each of the inserts isitself indexible.

The tool according to the present invention as shown in FIG. 1 comprisesa tool body that includes a holder 1 and a securing portion 9. Theholder 1 is provided at its free end with a number of insert pockets forreceiving replaceable, indexible inserts 3, 5, 7, the number of which inthe shown embodiment being three.

All inserts 3–7 are oriented such that their respective main planes Pextend laterally in relation to the longitudinal center axis CL of theholder. The “main plane” shall be understood as a plane which coincideswith the bottom surface of the insert.

As is shown in FIG. 1 the holder 1 is non-centrally (i.e.,eccentrically) located on the securing portion 9 of the tool body, whichis intended to be tightened firmly in a tool machine. The reason why theeccentric placement of the holder 1 is possible is that the toolaccording to the present invention is a turning tool and thus does notrotate during operation. However, it is possible to index the tool, i.e.rotate the securing portion 9 about an indexing axis in order to feed anew insert to an operative cutting location. That is, the indexing ofthe tool can take place by rotating the holder 1 about its longitudinalcenter axis CL which would thus define an indexing axis. Alternatively,or additionally, indexing could take place by rotating the securingportion 9 about its longitudinal center axis CL′ which would thus definean indexing axis.

In FIG. 2 the inserts 3, 5, 7 are shown more in detail, wherein theinsert 3 has been inclined such that its main plane P forms an acuteangle α with a perpendicular reference plane oriented perpendicularly tothe holder's center axis CL, and wherein the angle α lies in atangential reference plane i.e., a plane oriented generally tangentiallyrelative to a radius of the holder. Such an inclination could beachieved, for example, by rotating the insert 3 of FIG. 1 about an axisA defined by a radius of the holder 1 that passes through the insert'scenter axis E (see FIG. 2 for the axis E). From FIG. 2 it will beappreciated that a line L1 extending parallel to the main plane P froman axially forwardmost corner C1 of the insert's front cutting face andthrough the insert's center axis E forms the angle α with a referenceline R1 that lies in the perpendicular reference plane and also passesthrough both the insert's center axis E and the axially forwardmostcorner of the insert's front cutting face. The angle a has suitably avalue in the range −45≦α≦+45 wherein the angle is measured from thereference line RI, and where the angle α is positive above the referenceline R1 and negative under the reference line R1.

In FIG. 3 is shown how corresponding insert 103 on an alternative holder101 has been inclined at an angle β such that the main plane P forms anacute angle β with a perpendicular reference plane, i.e., a planeoriented perpendicularly to the holder's center axis CL, wherein theangle β lies in an axial reference plane i.e., a plane that contains theholder's center axis CL. The angle β could be formed, for example, byrotating the insert 3 of FIG. 1 about an axis F which is: (i) orientedtangent to a radius of the holder 1 and (ii) extends through theinsert's center axis E. It will be appreciated that a line L2 extendingparallel to the main plane of the insert 103 from an axially rearmostcorner of a front cutting face of the insert and through the insert'scenter axis E forms the angle β with a reference line R2 which lies inthe perpendicular reference plane and which also passes through both theinsert's center axis E and the axially rearwardmost corner of theinsert's front cutting face. The axially rearwardmost corner of theinsert's front cutting face lies adjacent the holder's center axis CL.The angle β has suitably a value in the range −45°≦β≦+45°, wherein theangle is measured from the reference line R2, and where the angle β ispositive above the reference line R2 and negative under the referenceline R2.

It will also be appreciated that within the scope of the invention, aninsert could be inclined by both of the angles α and β.

A important feature of the present invention is that the main plane ofeach of the inserts 3; 103, 5, 7 has a dimension extending laterally inrelation to the axial direction CL of the holder 1; 101, whereinaccording to the present invention also the inserts 3; 103 are regardedas extending laterally across the axial direction CL despite the factthat they are inclined at a certain angle. Generally, this expression“laterally” is given such an interpretation that not only is the insertlocated in a plane perpendicularly towards the axial direction CL isincluded but also the insert is inclined within the indicated angularrange.

With the embodiment shown in FIG. 4, insert 203 on an alternative holder201 has been displaced a certain distance d in the axial direction CLrelative to the remaining inserts 5 and 7. This promotes the tool'savailability to the work piece when chip forming machining is conducted.As shown in FIG. 4 each of the inserts 203, 5, 7 is orientedsubstantially perpendicular to the axis CL. However, one can within thelimits of the invention make arrangement such that or some of theinserts 203, 5, 7 are inclined in the manner shown in FIGS. 2 and/or 3.

In FIG. 5 shows how an embodiment of a tool according to the presentinvention is used. The holder 301 is now centrally (coaxially) orientedin relation to the securing portion 309. FIG. 5 shows schematically howone of three inserts 303, 305, 307, more exactly a copying insert 305,machines a work piece A3.

Even more detail is shown in FIG. 6 of the inserts of the tool accordingto FIG. 5, wherein these inserts represent a typical set up of inserts.From FIG. 6 it appears how the holder 301 is equipped with a turninginsert 303 for heavy duty machining, a copying insert 305 and athreading insert 307. These inserts 303, 305, 307 may been inclined at acertain angle α and/or β as above described.

Shown in FIG. 5 is how different forces affect the copying insert 305,wherein FT designates a tangential force; FA designates an axial force;and FR designates a radial force. The absolute biggest force thatinfluences the insert is the tangential force FT, which in theembodiment according to FIG. 5 has a direction along the longitudinaldirection of the holder 301. This means that the tangential force FT isabsorbed by the holder 301 without causing a pronounced deflection ofthe holder 301. The force situation as shown in FIG. 5 entails also lesstendency to vibrations than in conventional turning tools.

In FIG. 7 is shown how the tool according to the present invention isused in order to make use of the threading insert 307 to produce athread on the rotary work piece A3.

In FIG. 8 is shown an alternative embodiment of a tool according to thepresent invention. As is shown in FIG. 8 two replaceable indexibleinserts 403 and 405 are oriented in relation to the holder 401 accordingto the principles of the present invention, i.e., the main plane of theinserts 403 and 405 extends laterally of the axial direction CL for thetool. A third insert 407 of the tool according to FIG. 8 has aconventional orientation on the holder 401. In the embodiment shown inFIG. 8 the insert 403 is a turning insert while the insert 405constitutes a copying insert. The inserts 403 and 405 generally performdifferent types of machining, i.e. the insert 403 performs heavy dutymachining while the copying insert 405 performs a finish machining.

FIG. 9 shows examples of how the tool according to FIG. 8 is used whenmachining a rotary work piece A4. As is shown in FIG. 9 the conventionalorientation of the insert 407 causes this insert for example to becomeuseful for internal turning.

The turning tool according to the present invention thus carries anumber of exchangeable inserts, preferably of different types, whichentails that this turning tool by indexing thereof can be adjustedsimply and quickly between different kinds of turning operations.

Conceivable Modifications of the Invention

In the above described embodiments, the tool according to the presentinvention is equipped with inserts of three different types, which makesthe tool useful in three different kinds of machining operations.However, one can within the limits of the invention also provide toolsequipped with interchangeable inserts of only one or two types that arepresent in different quantities.

Generally, in all of the described embodiments of the tool according tothe present invention as described the inserts are secured into theirinsert pockets by central screws. As this is outstanding conventionaltechnique these screws have not been described in further detail. Withinthe limits of the present invention the interchangeable inserts might besecured in their insert pockets by alternative clamping means, wherein,in a not limiting sence, one example could include the use of a topclamp portion.

1. An indexible turning tool comprising a tool body including a securingportion and a holder projecting from the securing portion, the holderprovided with pockets receiving respective replaceable cutting inserts,the pockets arranged wherein indexing of the tool body about an indexingaxis brings one of the inserts into an operative cutting position,wherein one of the inserts has a main plane oriented laterally relativeto the indexing axis, each of the inserts having a plurality of cornersincluding a radially outermost corner spaced radially farther from theindexing axis than the other corners of the insert, wherein a referenceplane oriented perpendicularly to the indexing axis and passing throughthe radially outermost corner of the one insert is spaced axially fromthe radial outermost corner of at least one other insert, wherein themain plane of the at least one insert forms an acute angle α with aperpendicular reference plane oriented perpendicularly to the holder'scenter axis, wherein the angle α lies in a plane oriented generallytangentially relative to a radius of the holder.
 2. The indexibleturning tool according to claim 1 wherein the acute angle is in therange −45°≦α≦+45°.
 3. The indexible turning tool according to claim 1wherein at least an additional one of the inserts has its main planeoriented laterally relative to the holder's center axis, wherein theinserts whose main planes are oriented laterally of the holder's centeraxis are configured differently from one another.
 4. The indexibleturning tool according to claim 1 wherein respective radial spacings ofthe inserts from the holder's center axis are different from oneanother.
 5. The indexible turning tool according to claim 1 wherein theinserts are indexible relative to the holder and relative to each other.6. The indexible turning tool according to claim 1 wherein the holder'scenter axis is arranged eccentrically with respect to a centerlongitudinal axis of the securing portion.
 7. The indexible turning toolaccording to claim 1 wherein the holder's center axis is coincides witha longitudinal center axis of the securing portion.
 8. An indexibleturning tool comprising a tool body including a securing portion and aholder projecting from the securing portion, the holder provided withpockets receiving respective replaceable cutting inserts, the pocketsarranged wherein indexing of the tool body about an indexing axis bringsone of the inserts into an operative cutting position, wherein one ofthe inserts has a main plane oriented laterally relative to the indexingaxis, each of the inserts having a plurality of corners including aradially outermost corner spaced radially farther from the indexing axisthan the other corners of the insert, wherein a reference plane orientedperpendicularly to the indexing axis and passing through the radiallyoutermost corner of the one insert is spaced axially from the radialoutermost corner of at least one other insert, wherein the at least oneinsert forms an acute angle β with a perpendicular reference planeoriented perpendicularly to the holder's center axis, wherein the acuteangle lies in a plane containing the holder's center axis.
 9. Theindexible turning tool according to claim 4 wherein the acute angle isin the range −45°≦β≦+45°.
 10. An indexible turning tool comprising atool body including a securing portion and a holder projecting from thesecuring portion, the holder provided with pockets receiving respectivereplaceable cutting inserts, the pockets arranged wherein indexing ofthe tool body about an indexing axis brings one of the inserts into anoperative cutting position, wherein one of the inserts has a main planeoriented laterally relative to the indexing axis, each of the insertshaving a plurality of corners including a radially outermost cornerspaced radially farther from the indexing axis than the other corners ofthe insert, wherein a reference plane oriented perpendicularly to theindexing axis and passing through the radially outermost corner of theone insert is spaced axially from the radial outermost corner of atleast one other insert, wherein a main plane of at least one of theinserts is oriented substantially parallel to the holder's center axis.11. An indexible turning tool comprising a tool body including asecuring portion and a holder projecting from the securing portion, theholder provided with pockets receiving respective replaceable cuttinginserts, the pockets arranged wherein indexing of the tool body about anindexing axis brings one of the inserts into an operative cuttingposition, wherein one of the inserts has a main plane oriented laterallyrelative to the indexing axis, each of the inserts having a plurality ofcorners including a radially outermost corner spaced radially fartherfrom the indexing axis than the other corners of the insert, wherein areference plane oriented perpendicularly to the indexing axis andpassing through the radially outermost corner of the one insert isspaced axially from the radial outermost corner of at least one otherinsert, wherein the number of inserts consists of three, the threeinserts being spaced circumferentially about the holder's center axis.